docs: def validate_args(args):
      """Validate command-line arguments."""
      if not any([args.environment, args.stage, args.account]):
          sys.exit(NO_ACCT_OR_ENV_ERROR)
      if args.environment and args.account:
          sys.exit(ENV_AND_ACCT_ERROR)
      if args.environment and args.role:
          sys.exit(ENV_AND_ROLE_ERROR)